Historic Herdman's Mill is targeted twice by arsonists
Police are appealing for help in tracking down arsonists who set two fires at a derelict factory.
Herdman's Mill, at Mill Lane in Sion Mills was gutted by the blaze on Friday night before the attackers returned the next night and set it on fire again.
Police urged the public to avoid the factory as it remains in an unsafe condition.
In 2014, Herdman's Mill was bought by Strabane woman Margaret Loughrey for £1m after she won almost £27m in the Euromillions lottery draw.
Last October, the historic mill complex was seriously damaged in another blaze. And back in August 2011 the mill suffered major damage in another fire.
Sergeant Allen of Strabane PSNI said: "On the evening of Friday, June 10, a fire was started at Herdman's Mill, causing substantial damage.
A second fire was started at around 8.30pm on Saturday, June 11, causing further damage.
"I would appeal to anyone with any information to contact police in Strabane on 101.
"Information can also be given anonymously Crimestoppers on 0800 555 111."